Question

Consider following unit values of energy
I. $1L$ atm,
II. $1$ erg,
III. $1J$
IV. kcal,
Increasing order of these values is

• A. I = II = Ill = IV
• B. I < II < III < IV
• C. II < III < I < IV
• D. IV < l < III < II

Answer 1

Answer: (C)

$R=0.0821Latmmo{l}^{-1}{K}^{-1}$
$=8.314\times 10^7$ ergs $mo{l}^{-1}{K}^{-1}$
$=8.314Jmo{l}^{-1}{K}^{-1}$
$=0.002kcalmo{l}^{-1}{K}^{-1}$
$\therefore 1L$ atm $=\frac{R}{0.0821}$ mol $k$
$1$ erg$=\frac{R}{8.314\times 10^7}$ mol $k$
$1J=\frac{R}{8.314}$ mol $K$
$1$ kcal $=\frac{R}{0.002}$ mol $K$
Thus, $I<II<I<IV$